Conventional electrocardiogram (ECG) devices typically employ a twelve-lead system. ECG systems employing more than twelve leads are also known. The conventional twelve-lead systems typically use individual leads that are connected to a patient; whereas in systems using more than 12 leads, such as an 80 lead system, the electrodes are generally arranged as part of an electrode vest that is adhered to the patient. By way of example, one type of electrode vest is described in U.S. Pat. No. 6,055,448. Electrode vests are typically flat and somewhat flexible, but are prone to kinking and wrinkling when positioned on a pliable curved surface such as the human body. Moreover, the electrode vests include long finger-like sections that make them a bit unwieldy and difficult to place on the body without the sections sticking together or sticking to an unwanted portion of the body.
FIGS. 1A and 1B illustrate a prior art sensor device 100 in the form of a vest that may be applied to a human patient's torso for receiving bioelectric signals or delivering stimulating signals to a patient. Anterior portion 110 (FIG. 1A) is suitable for placing on the front of the patient's thoracic region and includes a flexible, dielectric substrate 111 having vertical, finger-like projections 120. Horizontal, common substrate portions 112 join the finger-like projections 120. A plurality of sensors or electrodes 130 are connected to a network of conductive traces 140 and are located on substrate 111. Bioelectric signals from the patient are detected by the sensors 130 and transmitted via traces 140 to a suitable medical device, such as an electrocardiogram (ECG) base unit (not shown).
FIG. 1B shows a posterior portion 210 of prior art device 100. Posterior portion 210 similarly includes flexible substrate 211 having vertical, finger-like projections 220. Horizontal, common substrate portions 212 join the finger-like projections 220. A plurality of sensors or electrodes 230 are connected to a network of conductive traces 240 and are located on substrate 211. Bioelectric signals from the patent are detected by the sensors 230 and transmitted via traces 240 to an ECG base unit or other suitable medical device (not shown).
FIGS. 2A and 2B illustrate another embodiment of a prior art sensor device 200 also in the form of a vest. For purposes of clarity, similar elements in FIGS. 1A-1B and 2A-2B are identified with identical reference numbers. Absent from the embodiment of the anterior portion 110 (FIG. 2A) and posterior portion 210 (FIG. 2B) of prior art device 200 are the common substrate portions 112, 212 connecting finger-like projections 120, 220, the absence of which essentially lengthen the finger-like projections 120, 220.
As can be appreciated from the foregoing discussion of prior art sensor devices 100, 200 and as illustrated in FIGS. 1A-B, 2A-B, the flexible nature of substrate 111, 211 along with the long finger-like projections 120, 220 may make the sensor device 100, 200 difficult to handle and, as a result, difficult to properly and accurately place the electrodes 130, 230 on the patient's body. Further, the long vertical network of conductive traces may stiffen portions of the sensor device 100, 200 and cause the device 100, 200 to buckle or wrinkle when the patient moves, resulting in the electrodes 130, 230 becoming dislodged from the patient.